# there're differences between string test and numeric test 

## string test 

# string equality test
if [ 'test' = 'test' ]; then
    echo 'left string is equal to right string.'
else 
    echo 'left string is not equal to right string.'
fi

# string inequality test
if [ 'test' != 'Test' ]; then
    echo 'left string is not equal to right string.'
else 
    echo 'left string is equal to right string.'
fi


## numeric test 

# numeric equality test
left_num=0x3
right_num=3

if [ $left_num -eq $right_num ]; then 
    echo 'left num is equal to right num'
else 
    echo 'left num is not equal to right num'
fi

# numeric inequality test 
if [ $left_num -ne $right_num ]; then 
    echo "$left_num is not equal to $right_num";
else 
    echo "$left_num is equal to $right_num.";
fi

# other replacement
# -lt: less than 
# -gt: greater than
# -le: less than or equal to 
# -ge: greater than or equal to 
